Patent GB-412933-A (GB)
Title: Catalytic thermal conversion of hydrocarbon gases or their mixtures into benzene and its homologues and higher aromatic hydrocarbons
IPC: C07C15/00
Filed: 1932-09-28
Abstract: In the catalytic thermal conversion of hydrocarbon gases or gas mixtures into aromatic hydrocarbons, those catalysts which are porous, e.g. graphite, have their pores sealed with catalytic metal, e.g. by producing the catalytic metal in distributed form in the pores by reduction of the corresponding metal salt.  Reference has been directed by the Comptroller to Specifications 361,944, [Group IV], 364,144, 366,494, 368,257, 368,291; and 369,351, [Group IV].ALSO:Benzene and its homologues and higher aromatic hydrocarbons are manufactured by subjecting hydrocarbon gases or gas mixtures to contact at a temperature between about 600 DEG  and 1200 DEG  C. with catalytic material presenting extensive surface contacting conditions, and withdrawing the resulting aromatic hydrocarbon vapours before destructive action occurs.  The following catalysts are specified: iron, nickel, steel and alloys thereof, copper, cobalt, manganese, chromium, molybdenum, tungsten, tin, aluminium, alkali metals, alkaline earth metals, silicon, boron, and alloys, mixtures or compounds (e.g. oxides, carbonates or other salts) thereof, pumice, fire brick, silica gel, porcelain, silica or refractory products of electric furnace origin such as electric furnace produced alloys of iron and aluminium, siloxicon and those oxygen compounds of silicon immediately surrounding the carborundum zone in the electric furnace, silicon itself, forms of electric furnace treated carbon, electric furnace fused alumina, carbides, nitrides, silicides, borides, or mixtures or compounds thereof.  If the catalysts are porous, e.g. graphite, the pores should be sealed with catalytic metal, e.g. by producing the catalytic metal in distributed form in the pores by reduction of the corresponding metal salt.  Suitable starting materials are: gases formed during the conversion of tar acids or mixtures of creosote oil and mineral oil to aromatic hydrocarbons, gases made during high and low temperature coal distillation, carburetted water gas, gases resulting from distilling or gasification of lignites, gases resulting from cracking of any of the bye-products of coal distillation or its fractions or gases resulting from the distillation, cracking or gasification of oil products, Pintsch gas, oil gas, and in general the gases or mixtures of gases resulting from the heat treatment of carbonaceous and hydrocarbon material derived as a whole or fractionally from the heat treatment of coal of all grades from peat to anthracite, also the gases resulting from the heat treatment of mineral oils of all grades, asphalt, bitumens or shale oils, and the gases resulting from the heat treatment of mixtures of coal and oil in any proportion with or without steam.  If the gases are not directly available they can be produced in a preliminary process carried out below 600 DEG  C., e.g. in the conversion of tar acids to benzene or the catalytic conversion of water gas to methane at 350--400 DEG  C. with subsequent elimination of carbon dioxide.  The relation between rate of flow and temperature may be determined by experience, the presence of hydrogen in the product and the deposition of carbon on the catalyst indicating too slow a rate for a given temperature or too high a temperature for a given rate of flow.  Any gases not converted in the first cycle may be re-run, if desired after admixture with fresh gases.  The reaction may be carried out at atmospheric, sub-atmospheric or slightly elevated pressures, and may take place in an electrically heated apparatus, or, continuously or intermittently, in any suitable high temperature furnace.  The apparatus is preferably made from electric furnace products of the kinds mentioned above.  The products are suitable for antiknock additions to motive fuel.  In examples: (1) a mixture of equal parts of creosote oil and mineral oil is passed through a preheating coil and thence at atmospheric pressure through a catalytic zone at 450--550 DEG  C., and the gas mixture formed, of which three typical analyses are given and which consists of paraffinic and olefinic hydrocarbons together with carbon dioxide, hydrogen sulphide, oxygen, carbon monoxide, hydrogen and nitrogen, is passed, preferably after separating the admixed condensible vapours, through a chamber at 800--850 DEG  C. filled with discs of catalytic material; (2) gases from the destructive distillation of oils, e.g. Pintsch gas, consisting of unsaturated and saturated hydrocarbons and hydrogen &c., or gases consisting of butane, propane, ethane and methane, or gases consisting of propylene, butylene and ethylene obtained by cracking oils of Diesel oil fraction or lighter and passing them at 700 DEG C. through pipes made, for example, of copper or chromium and filled with copper or chromium rings, or made of electric furnace products, are passed at 700--800 DEG  C. through a catalytic zone as in (1); (3) a carburetted water gas is passed through a catalytic zone at about 450 DEG  C. to produce a mixture of methane and olefines, which is passed at 800 DEG  C. through a catalytic zone, as in (1); (4) an olefine gas made by cracking a coal distillation product or by cracking oil or both coal and oil is similarly treated. Specification 397,468 is referred to in the Provisional Specification.  Reference has been directed by the Comptroller to Specifications 361,944, 364,144, 366,494, 368,257, 368,291, and 369,351.